Conventionally, a ship is provided with a main operation unit that is for operating a rotation speed of an engine mounted thereon. The main operation unit is connected to an engine control unit (ECU) that is for controlling the engine. The ship's operator can change the rotation speed of the engine by operating this main operation unit.
There are cases when an auxiliary operation unit is provided with the ship in addition to the main operation unit. The auxiliary operation unit is provided for operating the rotation speed of the engine instead of the main operation unit when the main operation unit is in an unsatisfactory condition. Patent Document 1 discloses an engine rotation speed control device in which these types of two operation units are provided.
In the engine rotation speed control device of Patent Document 1, the engine control unit is configured to be capable of detecting that disconnection occurs between a remote control lever (a main operation unit) and the engine control unit. When this disconnection is detected and other predetermined conditions are satisfied, the engine rotation speed control unit controls such that the engine rotation speed can be operated by an auxiliary throttle dial (an auxiliary operation unit).